1. Field of the Invention
The present invention relates to an analytical device and a method for the analysis of biochemicals, microbes and cells utilizing a piezoelectric crystal biosensor.
2. Description of the Prior Art
Various methods for the determination of biochemicals, microbes and cells have included liquid chromatography, electrophoresis, direct observation of agglutination with the naked eyes, and other analytical methods, applying amplification with enzymes, fluorescence chemicals and radio isotopes (EIA, FIA, RIA).
Particularly, for the detection a pathogenic microorganism, a conventional method is comprised adding an antibody solution drop to a microbial suspension and observing the agglutination with the naked eye by using an agglutination plate. Recently, a system for the judgement of the agglutination has been developed, employing an image processing system equipped with a microscope. Further, a method applied to electrochemical determination and immuno reaction has been known. In this method, a microorganism is bound to an antibody immobilized on an organic film and the aimed concentration thereof is determined by measuring a change in the membrane potential.
On the other hand, for immunoassay, a surface acoustic wave (SAW) device has been developed, and one saw device is reported in the following document: J. E. Roederer and G. J. Bastiaans, Anal. Chem. 1983, 55, 2333-2336. This reference discloses that the determination of human IgG is carried out by promoting specific adsorption between immobilized goat anti-human IgG and human IgG at the surface of SAW device. The problem in the above methods, especially in agultination methods, are that the aggultination judged with the naked eye requires those skilled in the art. In addition, these methods give a poor quantitative result and can be hardly automated.
Furthermore, these conventional methods have some disadvantages in that they give poor sensitivity and require troublesome operation.
The image processing system has a large scale and requires considerable cost. The method, utilizing membrane potential, requires troublesome operations and can be hardly automated.
The other methods, for the immunoassay such as EIA, FIA and RIA, although they have a good sensitivity, require, also, troublesome operations.
The SAW device, for human IgG, only has a roughly determination range of human IgG: 0.0225-2.25 mg/ml.